Hi-Flow Cats vs. Resonated Cat Pipes
 

I'm new to the tuning market. So can somebody explain to me what the differences between resonated vs. non-resonated test pipes, high flow cats, and long tube headers are? I'm looking for something that will give the largest horsepower gain, but I am confused on what to get.

Test pipes give you the largest gains in HP but you lose torque. HFC's are needed if you live in a state where inspections are done. I would suggest Motordyne ART pipes as you'll gain a lot of HP AND TORQUE!

Largest HP (Less retrictive)=Test Pipes
Street legal and somewhat quieter=High Flow Cats

Resonaters reduce "rasp" and "drone" noises from opening up the exhaust.

Here's about as good a breakdown as I can make away from home:

Stock Cats

• Suck

High Flow Cats (HFC's)

• Either Ceramic or Metallic Core - You'll want Ceramic, last longer, least prone to core ruptures
• Better flow than stock cats, but less than test pipes or headers
• 50/50 chance of passing sniffer tests
• Still retain 'Stock' look for visual tests
• Mild HP/TQ gain

(Resonated) Test Pipes

• No Cat whatsoever
• Will NOT pass sniffer tests
• Better flow than Stock/HFCs, but less cleanly than headers or ART pipes
• Resonated TPs will have less rasp/drone than Non-Res but performance is unaffected
• Moderate HP/TQ gain

Advanced Resonance Test Pipes (ART Pipes)

• No Cat whatsoever
• Will NOT pass sniffer tests
• Improved flow over regular (R)TP's
• Slightly nulled rasp, but still noticeable
• Slightly more HP/TQ output than regular (R)TP's

Long Tube Headers (LTH's)

• Sex
• As with (R)TPs and ART Pipes, no cat whatsoever
• Smoother flow than all previously mentioned parts
• Distinctive sound, slightly higher pitched yet quieter idle
• Most Dyno proven gains out of the group.
• Hardest Install of the bunch, but looks the best when completed.

Hope this helps with the basic idea. :tiphat:

Sounds about right Chris. LTH are expensive though and my only other argument is the ART pipes with an aftermarket header would put out more power than the just regular LTH because of the ART pipe design and would still cost less. This is just a theory because LTH are just a regular test pipe and header in one piece and the ART pipe is better than a regular test pipe, therefore it should give better results when mated to a header.

Isn't it like 5-6 hours for a shop to install headers?

OP, you're going to have to look into the emissions laws in your area to decide how you'd like to approach your mods. If they do inspections you'll have to stick to HFC's or make buddies with a shop like I did in New York and I was able to run around with limo tint on my car.

great break down man, :).. But headers have been said to be not worth the $$$ or the install time for the WHP you get (At least over on G37.com) .. I would only go either HFC or ART pipes.

Thanks for the help Chris that really makes it simple for me!

Any thoughts on Fast Intentions' "Resonated Cat Pipes"? From what I understand, they're HFC with a resonator. So, you get the performance of a HFC with the added "silencing" of a resonator. But wouldn't the resonator cause restriction, therefore defeating the purpose?

Yes and no. The cells inside the HFC are less restrictive than stock, and the resonator they use is probably a high flow model.

Great question!

Our resonators are straight through perforated core. No baffles or louvers. They do not hinder the performance at all!

So to answer your question, the added resonator is strictly designed to cut down the sound.

If you have any questions or would like to place an order, please do not hesitate to call me directly...

Thank you, Tony

Is Berk the only brand that utilizes the stock brackets?

I wouldn't worry about the brackets. Originally my berk cats were installed with the bracket but it ended up making a lot of noise. Removed it for a weight savings mod!

Noise? I would expect the bracket to prevent vibration and movement. Weird.

It was weird. The noise would only be present during deceleration.

I just learned that the CNT test pipes has the bracket mounts too.

ART test pipes now have version 2 which have brackets and added ceramic coating. These are prolly the best test pipes money can buy. NO CELS..great resonated sound and now the bracket to minimize vibration.

PIC..Version1 below 2 above:

http://img265.imageshack.us/img265/6500/phot2.jpg

Haha actually there was like 3 versions before those too. The first version had a flat resonator, then they made them rounded for midrange power, then start polishing them but beads landed up inside the resonator. Then they made ceramic titanium coated (that's what I have), then they began the polished ones again, and now they finally have tabs on them and they removed the steel wool. Haha these will undoubtably change again.

I have the Fast Intention HFC's and i do not believe any brackets were needed. A shop did the install so i could be wrong but dont think so...

Also,

how do Advanced resonated test pipes differ from test pipes to get better gains?? I thought test pipes were basically just straight thru pipes, how does it get better than that?

Advanced Resonance Tuning (ART pipes) - MY350Z.COM Forums


It's called a Helmholtz resonator. google it.

Thats intersting but I would like to see some actual dyno results to show the differences... Sorry, im a skeptical person lol

Thank you guys for all the great info.

-from another uneducated in tuning japanese

Scroll down to charts on this link..compares ART to test pipes:

Motordyne ART Pipes (TEST Pipes w/ a twisty twist) : G35 and G37 General Discussions

There are many different dyno comparisons

Hmmnn, Im just not seeing it. None of which have been dyno's comparing test pipes, only the ART's to HFC's.... and whats on that link is not a dyno test, it is a chart...

I'm just going to bump this up after a year of hibernation. Footloose is absolutely wrong regarding ART Pipe with an aftermarket shorty header vs LTH's. Longer primaries improve scavenging and merge the exhaust together in pulses. Longer primaries generally improve torque over shorter ones. 1 3/4" diameter tubing generally improves torque over 1 7/8ths" Stepped headers use a combination of the two different sizes to improve low end torque and keep top end power. A tuned header means tuning the length of the primaries to the powerband of the engine. LTH's improve scavenging and assists in pulling old exhaust gasses out of the combustion chamber. The higher the rpm, the less critical this is, but is VERY important for making power and torque down low and below 4k rpm. Both the PPE LTH's and the F.I LTH exit at 2.5" and has the benefit of not being restricted to 2 1/4" when connecting to the stock header.

Shorty headers attempt to do the same in a smaller package. Primary length is limited, they will not be stepped, and can only improve flow to a certain degree. Attaching an ART pipe will improve performance... over the stock cats or maybe a standard test pipe, but it's still just a pipe that can't possibly do the same job as having LTH's doing. The only shorty/test pipe combo that came close to LTH's were the momentum headers and TP. But there is no direct comparison as gains made included VVEL tuning.

Even with superchargers, they flow so much better, boost pressure is reduced, measuring at the same boost pressure, the SC with the LTH's will always make more power, as it's now running more efficient per psi.

The only issue with headers is the PITA install and costs. If you plan on going turbo, save your money and don't buy them.

I said it was just my theory, so chill.

LTH's definitely have the potential due to equal length and the exhaust pulses, no doubt. However, it's been proven that shortys dyno around 1-2whp, therefore not cost effective and LTH's are even more expensive. Not worth the money (in my opinion).

I see you have LTH's and dyno at 310whp on a dyno jet, whereas I dyno at 319.5whp on dyno dynamics, and 298whp on the mustang dyno.....

We need actual dyno comparisons on the same dyno if anybody has some out there.

It's plenty cold outside :) Cost effectiveness, yes, not very cost effective, but you can find good deals on em. Hard to compare two different vehicles on two dyno's. The delta between my baseline STD and my current dyno using STD is roughly 50whp.
The headers and exhaust were good for 30 of that. No gains on tuning currently :(

Whenever NewYorkJon34 parts his car I will do a dyno comparison if he parts with his LTH's for a decent price. I will do before and after at HP Logic for everyone. I know he's been searching for a 2013/2014 GT500 he should part out sometime soon. :tiphat: